Light bulb filament



FIG. 1 is a perspective front View of a light bulb filament;

FIG. 2 is a left side View thereof;

FIG. 3 is a front View thereof;

FIG. 4 is a right side View thereof;

FIG. 5 is a rear View thereof;

FIG. 6 is a top plan View thereof;

FIG. 7 is a bottom plan View thereof; and,

FIG. 8 is a perspective rear View thereof. 

CLAIM The ornamental design for a light bulb filament, as shown and described. 